Whiscash, The Whiskers Pokémon. It is very territorial. It repels foes by setting off tremors that extend over a three-mile radius.As a result of causing tremors by thrashing about, it developed the ability to foretell real quakes. It is extremely protective of its territory. If any foe approaches, it attacks using vicious tremors. It claims a large swamp to itself. If a foe comes near it, it sets off tremors by thrashing around.

Overview

Whiscash came in at the wrong time. It came in with Swampert, a vastly superior Pokémon in pretty much every field. In the new generations it got Dragon Dance, which gives it something new to play with that no other Water/Ground has. I'm not saying it is good, but it gives it something. It has nice HP which can be handy on all sets, and gives it the option of going down the bulky Water route. Thanks to having equally bad Attack and Special Attack, it can run a choice set for either side of the attacking spectrum. Whiscash isn't really that good a Pokémon... even its design is dumb. Look at that stupid smile! It looks so moronic. I dunno, I guess it could be alright in the lower tiers.

Abilities

Oblivious: Makes you immune to infatuation. Basically, stops Cute Charm and Attract. Yeah, useless.Anticipation: If the opponent has a super effective move, this ability lets you know. Only really handy for Hidden Power [Grass].Hydration: This is a pretty good ability. Basically makes you immune to status in rain. It cures any status at the end of the turn. Hydration+Rest is a pretty effective combo.

Sweep the opponent in a completely embarrassing way with this ridiculous Pokémon. Dragon Dance boosts your Attack and Speed, making you “threatening”. Waterfall is a great STAB attack and the flinch works well once you get a few boosts. Earthquake gets STAB and hits crazy hard. Also pairs up well with Water. Substitute works brilliantly with Whiscash's huge HP. Stone Edge gives you a way of hitting Flying/Dragons and things like that. Rest is used only if you run Hydration and rain. It's basically a Full Restore.

If you are at 1 HP, Flail has an obscene 200 base power. That's amazing. Waterfall and Earthquake make up your alternate attacks, and I don't think anything resists that combo except for Shedinja. Dragon Dance boosts your Speed and Attack, both required to be high for this set to work.

Hit as hard as you can, then run away and do it again. Earthquake hits stupid hard and is amazing. Waterfall hits pretty hard and is a great move. Stone Edge hits fairly hard even without STAB and provides good coverage. Return hits harder than Stone Edge by 2 base power, and combos surprisingly well with Water moves. Spark adds some extra coverage.

Special version of the previous set. Surf is reliable and strong. Scald is a little weaker but has a chance to burn. Hydro Pump is less accurate but hits harder than anything else. Ice Beam provides great coverage and is a strong special attack regardless. Earth Power is STAB. Your choice of Hidden Power depends on what you want to hit; Grass hits other Water/Grounds, Electric hits Flying/Waters, and Fire hits Steel/Bugs and 4x weak Pokémon.

Abuse Hydration as much as you can. Toxic deals a lot of damage over time, and this set is designed to stall. Substitute blocks damage, which is awesome. Protect is an option over it so you don't expend 25% of your health. Earthquake hits Steels hard but has a lot of immunities, where as Scald can burn and has... way less immunities than Ground. Rest works amazingly with rain and Hydration as it is a free full heal, with no side effects.

EVs & Natures

How does Whiscash even get Dragon Dance
If you aren't running Substitute, you can drop all the bulk and focus purely on Attack and Speed.

What is that flailing on the end of my line?
There's no reason to go anything but 252/252. You want to get to 1 HP, not take hits.

Whis choice do I make? (band)
Replace some Speed for bulk if you like.

Whis choice do I make? (specs)
Replace some Speed for bulk if you like.

Hydrastall
Max Leftovers recovery, but you can drop it to 404 HP or just go to max. The defences are equal as you will be taking hits from both sides of the spectrum, but you could run a heavily Defence focused set, or Special Defence focused. If you are feeling lucky about Scald burning, max Special Defence wouldn't go a miss as the burn would halve the opponent's Attack anyway.

Other Options

Amnesia, Aqua Tail, Endure, Sleep Talk, Tickle, Whirlpool, Zen HeadbuttAmnesia doubles your Special Defence. Could be worse.Aqua Tail is a stronger but less accurate Waterfall.Endure makes sure you are at 1 HP, but it means you have to forgo a move slot on the Flail set.Sleep Talk comes with Dream World Barboach. Not too useful considering the nature of Hydration.Tickle can set up a team member by forcing a switch.Whirlpool sort of acts like Mean Look, but damages slightly and isn't a permanent trap.Zen Headbutt can provide some coverage.

Double & Triple Battle Options

Gets Surf and Earthquake which are both useful. It really doesn't get much that sets it apart from any other Water/Ground. Only in singles do the above sets work really. I guess it can abuse Hydration in doubles.

Partners

Politoed. It means you have to use Whiscash in OU, but Hydration is so good it is worth it. Otherwise, use it on a rain team. You need defence against Grass types. Running a Fire, Steel, Flying, Poison, whatever type would be really helpful. A strong Fighting type to get rid of Ferrothorn is ideal.

Countering Whiscash

Grass types... fine, I'll list them. Uh... any pure Grass type does really well. Cradily is notable now it gets Storm Drain. Meganium, Lilligant, I'm bored of listing Grass Pokémon already. They are the way to go though. Bulky Waters do well too, but should be cautious of Toxic and STAB Earthquakes. Milotic, Blastoise, Quagsire (especially with Unaware). General bulky physical walls like Weezing are great too. Outside of rain, Whiscash is very vulnerable to status. Ferrothorn obviously walls Whiscash, just like it walls every single Water in the game. Virizion is another OU Grass that really ruins Whiscash. I'd talk about revenge killing, but it is obvious it can be done and how to do it. Whiscash doesn't hit hard, so if you resist its attack, you can most likely beat it.